This invention relates in general to respirators and in particular to a new and useful arrangement for cooling the inhalation line of such respirators.
Respirators are classified as cycle devices and as oscillatory respirators. In the first group the cycled respiratory air is sent for regeneration through a carbon dioxide absorption cartridge and then returned to the wearer after addition of the consumed oxygen. In the second group, the exhalation air is passed through a chemical cartridge into a respiration bag and is thence inhaled again as inhalation air by the same route. In the chemical cartridge the carbon dioxide is bound and oxygen is chemically set free, so that the oxygen is replaced. The chemical processes in the absorption cartridge in the cycle cartridge and in the chemical cartridge of the oscillatory respiration method are exothermic.
A known respirator with cycled respiratory air contains, in a housing chamber with a breathing bag and in another chamber, the material absorbing the carbon dioxide. The consumed oxygen is replenished from an oxygen bottle disposed below the housing and passed via a line to the chamber with the breathing bag. Into this chamber is passed also the exhalation air after having been freed from the carbon dioxide in the other chamber. Above the first chamber, in another chamber, is a liquid coolant, possibly water ice, which in liquid form wettingly penetrates through connecting tubes into a covering of an absorbent porous material pulled around the housing. The surrounding air can flow over the covering and in so doing it can evaporate the moisture. With the negative heat of evaporation the cycled respiratory air heated in the carbon dioxide-absorbing material is to be cooled. The cooling effect greatly depends on the quantity ratios of the ambient air conducted externally of the covering and of the respiratory air conducted inside the housing on the cooled outside wall. Besides, the wearer of the device must continuously carry the entire coolant supply together with the respirator. (DE-PS No. 12 50 272).
Another known respirator with oscillatory respiration consists of a CO.sub.2 binding and oxygen releasing chemical cartridge connected at one end to a breathing bag and at the other end to a mouthpiece. Between the mouthpiece and the chemical cartridge, a heat exchanger is interposed, which is alternately traversed by the inhalation air as well as by the exhalation air. The heat exchanger may be disposed either near the mouthpiece, at mid-length of the breathing tube, or in the upper portion of the chemical cartridge. The heat exchanger may consist of a packet of metal wires, chips, screens or the like. It is to operate by serving as moisture trap during the exhalation phase, with which moisture it then cools the inhalation air by evaporation during the inhalation phase. This presupposes a very dry inhalation air. (DE-PS No. 12 59 207).